Display the URL we will upload changes to for review

This gives the user the last chance to confirm where the change is
going to be sent to.  Knowing the review server URL will help the
user decide if continuing with the upload makes sense.

Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/subcmds/upload.py b/subcmds/upload.py
index 24bbc7b..01ba4ad 100644
--- a/subcmds/upload.py
+++ b/subcmds/upload.py
@@ -124,7 +124,7 @@
       for commit in list:
         print '         %s' % commit
 
-      sys.stdout.write('(y/n)? ')
+      sys.stdout.write('to %s (y/n)? ' % remote.review)
       answer = sys.stdin.readline().strip()
       answer = answer in ('y', 'Y', 'yes', '1', 'true', 't')